WECC’s Planning Department, in conjunction with the Studies Subcommittee, has completed the first of five Western Interconnection-wide studies to analyze potential reliability risks. The first study, Changes in System Inertia, investigated two questions:

• What is the potential minimum amount of inertia needed to prevent a large generation outage from causing underfrequency load shedding?
• What other reliability issues could occur with low system inertia?